Invited Lectures

Old age was earlier connected with edentulousness and dentures. Today in Sweden, as well as in the rest of Western Europe, we keep our own teeth high up in the ages or receive fixed tooth replacements. A well preserved chewing function is correlated to many aspects of good health and quality of life, even preserved cognitive functions. It means a sufficient number of teeth in contact with each other but also teeth that do not cause pain or infections. This is a challenge and a paradox; we have succeeded to keep complete dentitions but also created an increased risk situation for oral and dental diseases. The elderly Swedes of today present a new oral scenario that dentistry is not quite prepared for.

A situation with a good dentition in a healthy elderly person can with decreased health and increased medication turn into an oral catastrophe. High medication usage causes oral dryness, which in turn increases the risk for caries and mucosal infections. For frail elderly with swallowing difficulties, the risk for aspiration pneumonia will increase.

The ability to perform proper oral hygiene measures decreases in higher ages, due to functional limitations as well as decreased motivation. Daily life activities become so demanding that little energy is left for oral care. Sweden has a system of free oral health assessment at home and subsidized basic dental care to dependent elderly. It works well in special facilities but less for dependent elderly supported by home care aides, an expanding group.

Preventive dentistry measures and prolonged life span resulted in “dental success”, that requires a changed dental market where both traditional dentistry and oral care education will be offered as well as logistic improvements to help the elderly to keep a good oral health.

Dental age estimation – past and present

Tore Solheim

Institute of Oral Biology, Dental Faculty, University of Oslo, Norway

This lecture will present some important historical works for age estimation. Based on 45 years of practical experience, the discussion will cover both age estimation of children and adolescents using dental developmental stages and adults using dental regressive changes will be discussed. Recommended techniques for cases involving children, mostly adopted from western countries are presented. Also techniques for asylum seekers pretending to be below 18 years and techniques used for age estimation of adult persons who claim to be given wrong age when they came to our country are discussed. Age estimation can be performed in different ways. Either you use a specific method and present the results often with standard deviation. Alternatively you use your expertise as a dentist and assess the age visually and then modify your opinion after the calculation of the age according to scientific techniques. How to give the final age estimate will be discussed, as well as answering the problem in the actual case like what are the likelihood of the given age and the likelihood of an alternative age. Forensic odontologists have different approaches and views to this.

A New Application for Estimating Ancestry from Tooth Crown and Root Morphology: rASUDAS

G.Richard Scott

Department of Anthropology, University of Nevada Reno

Based on crown and root trait frequencies reported in The Anthropology of Modern Human Teeth, David Navega and João Coelho (Laboratory of Forensic Anthropology, University of Coimbra, Portugal) developed an application that assigns individuals to a geographic subdivision of humankind. All that is required is to take an individual dentition and score traits as present (in one or two categories, depending on range of expression), absent, or unobservable. The method was developed in two stages. First, Nei’s distance matrix was computed using each crown and root trait, from which a hierarchical clustering tree was created using UPGMA algorithm with complete linkage. Based on a visual inspection of the clustering tree, seven biogeographic population clusters were defined. Second, probabilistic biogeographic ancestry prediction models were fitted using naive Bayes classifier algorithm, a simple yet powerful technique that uses Bayes’ theorem as a prediction engine. This algorithm outputs the ancestral group and its associated posterior probability. It is called naive because the algorithm assumes total conditional independence between traits, which simplifies the full multivariate predictive density computation. Mathematical conditional independence is a strong assumption, but this conforms to the working assumption that crown and root traits are expressed independently of one another. To simplify and expand the usage of this method, a simple program and web application named rASUDAS was developed. Test runs on 150 data sheets from world populations arrived at correct classifications ranging from 57 to 92 percent, depending on the number of biogeographic groups included in the analysis.

Architecture and variation of the craniofacial system. Where is the architect?

Tomislav Lauc1,2,3

1 Dental Clinic Apolonija, Zagreb, Croatia

2 Study of Anthropology, Faculty of Social Sciences and Humanities, University of Zagreb, Zagreb, Croatia

3 Department of Dental Medicine, Faculty of Medicine, University of Osijek, Osijek, Croatia

During life and physical evolution, the human face continuously changes and adapts. Facial growth and development are under strong evolutionary influence. This is expressed by the mechanisms of adaptation and morphological changes, which result from genetic and environmental interaction. All five senses and nine functional units are located on a relatively small area, forming a unique cranial system. Facial architecture reflects the relationship of the neurocranium, body posture and different functional cranial components. Complex genetic cascade patterns of growth and development control determine the structure of the facial units. The activation and expression of gene groups are programmed by age with hormonal and mutual feedback systems playing an important role. By engaging in gene activation and expression processes, environmental factors modify the process of growth and development. Such adaptation to environmental conditions increases the variability of facial traits.

Craniofacial morphological variations have biological, social and medical implications. Are evolutionary changes an active or a passive process? How do facial traits change? Can we change ourselves by changing the environment? How close or distant are craniofacial anthropology and maxillofacial and dental medicine, and is it necessary to change thinking patterns in dental medicine and other medical fields? This lecture will try to answer the questions of how morphological variations arise, should we accept variations as disorders and disorders as variations, do evolutionary laws still apply today or will we rather refer to secondary changes, and where we can look for the architect of morphological variation of the human craniofacial skeleton.

HISTORICAL PERSPECTIVES OF DENTAL ANTHROPOLOGY

Kurt Werner Alt1,2

1Center of Natural and Cultural History of Man, Danube Private University, Krems-Stein, Austria

The History of Dental Anthropology dates back to antiquity. It has developed from a comparative anatomy of teeth, which dominated the research for a long time. Dental Anthropologys modern appearance occurred first 1840-45, when Richard Owen published his two-volume work Odontography. It includes the first comprehensive presentation of comparative anatomy of vertebrates. This publication gave an important impetus to the establishment of odontology as an independent field of study a short time later. At the beginning, mainly researchers from the fields of dental anatomy, ontogeny, phylogeny and palaeontology were involved at the further development of the discipline. For a long time their focus lay on comparative-morphological basic research and, in general, on theories of phylogeny of the teeth. In the 20th century, a new era of dental anthropology started. A key turning point was certainly also the appearance of Brothwell`s 1963 work Dental Anthropology. Nowadays teeth provide an important input to numerous natural and cultural historical issues. This is, above all, due to their significantly better preservation in the soil compared to bones. Disciplinary the circle of researchers expanded gradually to population biologists, evolutionary biologists, population geneticists, dentists, forensic medical and others. The last few decades have been marked by a strong increase in knowledge as well as by an increase in networking. Considering medical, biological, biogeographic, biomechanical, genetical, functional and ecological facts, complex clinical dental problems can be answered much more precise, too. The lecture outlines the historical development of dental anthropology, markes its turning points in history, introduces its protagonists and acknowledges the results, which have been achieved.

The grimace of battle – a mass grave from the thirty years’ war: dental, forensic and social aspects in the lives of soldiers

Kurt Werner Alt1,2

1Center of Natural and Cultural History of Man, Danube Private University, Krems-Stein, Austria

The Thirty Years’ War (1618–1648) was one of the most destructive conflicts in the European history. Violence, famine and diseases significantly decreased the European population. In November 1632 a small town in today’s Central Germany, was the setting of one of the greatest and bloodiest combats: the great Battle of Lützen. General Wallenstein and the Swedish King Gustav II Adolf were the most prominent actors on the battlefield, the latter was mortally wounded. More than 6.000 soldiers lost their lives, and – after looting – the dead bodies were buried in numerous mass graves. In summer 2011 archaeologists discovered one of these mass graves at the edge of Lützen. The complete grave was recovered en bloc and the skeletons were detailed analyzed in situ, accompanied by methods such as isotopic analyses (C/N, Sr/O), medical imaging techniques (X-ray, CT, DVT) and histology.

The grave contained the skeletal remains of 47 men with an age at death range from about 15 to 45 years; most of the men were 20-30 years old. One major intention was the reconstruction of the nature of violence in which these men died on the battlefield. Among numerous perimortem injuries a high number of cranial gunshot wounds were found. This kind of death and the caliber of the lead bullets helped to reconstruct the course of the combat, particularly in the area the soldiers died. Healed injuries, such as fractures of the upper and lower limbs or blunt and sharp force trauma to the cranium, provide information about healing conditions and insufficient medical treatment. Poor hygiene and long lasting deprivations have left osteological traces as well and reflects the adverse living conditions during wartime.